The present invention relates to an electronic component used for various electronic apparatus, particularly to an electronic component comprising an electrolytic solution and electronic component element.
As an electronic component comprising an electrolytic solution and an electronic component element, an example of an aluminum electrolytic capacitor will be described in the following.
A conventional aluminum electrolytic capacitor comprises an electrolytic solution for driving, a capacitor element, a metallic case, a sealing member, a positive electrode lead wire, a negative electrode lead wire, and a seating plate.
A capacitor element impregnated with an electrolytic solution for driving is stored in the metallic case. The sealing member has elasticity and seals the opening of the metallic case. Each of the positive electrode lead wire and the negative electrode lead wire is led out of the capacitor element.
In a conventional aluminum electrolytic capacitor having such configuration, the electrolytic solution for driving contains ethylene glycol as main solvent, and ammonium salt of organic acid added to the main solvent. As the sealing member, rubber made of styrene butadiene rubber or ethylene propylene rubber is used.
Further, in order to assure reliability over a wide range of temperatures, xcex3-butyrolactone is recently employed in place of ethylene glycol. Accordingly, since ammonium salt of organic acid, that is an electrolytic component conventionally employed, is low in electric conductivity of the electrolytic solution for driving, quaternary ammonium salt of organic acid has become to be used in place of ammonium salt of organic acid conventionally employed.
Also, the change of such electrolytic solution for driving is giving rise to the use of isobutylene, isobutylene rubber (that is, butyl rubber) having excellent air-tightness as the sealing member.
However, in the case of a conventional electrolytic capacitor obtained by combining a sealing member formed of butyl rubber having excellent air-tightness with an electrolytic solution for driving using quaternary ammonium salt of organic acid as electrolyte, the electrolytic solution for driving causes bad influences to the sealing member when subjected to a life test at high temperatures or under high-temperature high-humidity conditions, resulting in lowering of air-tightness of the sealing member. Consequently, the electrolytic solution for driving stored together with the capacitor element is volatilized in the metallic case. Further, in a reflow test using solder containing no lead, conducted on a conventional electrolytic capacitor, the sealing member is deformed and, resulting in generation of mounting trouble.
A conventional electronic component comprising an electronic component element having an electrolytic solution for driving involves such problems as lowering of air-tightness and generation of mounting trouble.
The present invention is intended to provide an electronic component having excellent reliability which is able to prevent lowering of air-tightness of the sealing member and also generation of mounting trouble.
An electronic component of the present invention comprises:
a case having an opening;
an electronic component element installed in the case;
an electrolytic solution disposed in the case;
and a sealing member disposed to seal the opening of the case,
wherein the sealing member has elasticity and comprises a cross-linked structure of compound, and the compound contains butyl rubber polymer as main component, phenol-based additive, and silane-based additive.
By this configuration, the sealing member will be improved in air-tightness. Further, the electrolytic solution is prevented from evaporating and leaking out of the case. Also, generation of mounting trouble may be prevented when the electronic component is actually mounted on a wiring board. Thus, it is possible to obtain an electronic component having excellent reliability.